Caught in the Act!

 Leighton Meester, brunching with boyfriend Sebastian Stan and two male friends at Isabella's on New York's Upper West Side. The Gossip Girl star ordered a burger with bacon, cheddar and fried onions. And while she and Stan weren't super lovey-dovey at the table, a source says that "they were relaxed" with each other as they dined outside.

 In Texas to film her new movie Machete, Jessica Alba stepped out for dinner with hubby Cash Warren at Al Biernat's steakhouse in Dallas. The two drove in from Austin for their meal, and dined on tuna tartare tacos, bone-in filet mignon and some mac and cheese as well as champagne with dinner. Before her big meal out, Alba was spotted shopping at a Goodwill in south Austin, where she picked up some moccasins for her daughter.

 Despite the nearly 100-degree weather, Avril Lavigne stayed zipped up in her sweatshirt with her hood over her head while shopping at Blue & Cream in East Hampton, N.Y. The singer bought some of the store's private label Lamptons T-shirts. Lavigne also enjoyed the nightlife, partying at Axe Lounge early in the weekend followed by a night at the Southampton Carnival – complete with rides and carnival games – with Blue & Cream's owner.

 Grey's Anatomy's Justin Chambers and wife Keisha, cozying up at Music Mogul.com's Talent Search finals at L.A.'s House of Blues. "The two cuddled in a table on the balcony directly in front of the stage" as they discussed the competition, says an eyewitness.

 Vince Vaughn and fiancée Kyla Weber rooted for the Chicago Cubs as they faced off against the Los Angeles Dodgers on a blazing hot afternoon at Dodger Stadium. The two were dressed in full-on Cubs apparel, but Vaughn also reserved some affection for Weber. "He spent most of the game with his arm casually draped around her when he wasn't clapping for his team," an onlooker says.